1. Field of the Invention
The present invention relates generally to an electronic testing apparatus, and more particularly to a flexible microelectronic probe useful for testing integrated and hybrid/electronic circuits.
2. Description of the Prior Art
Recent developments in hybrid and integrated electronic circuits have resulted in progressive miniaturization of these devices. In the manufacture of these circuits, it is necessary to conduct tests to determine the circuit's electrical characteristics, in order to discover defective devices prior to or after packaging. Further, it is a common practice of the purchaser of such devices to conduct tests prior to use in the equipment in which the devices are installed. This multiple testing demands testing equipment capable of performing these tests at high rates of speed with precision.
With regard to such test equipment, there has been developed test probe cards which generally consist of an insulating printed circuit board having an opening to provide access to an integrated circuit or electronic circuit positioned adjacent to, or underneath the board. The opening is surrounded by a ring of test probes, each of which is bound to the circuit board and each of which has a probe for making contact to a predetermined contact pad on the circuit under test.
Because the conductive pads on each circuit under test are relatively small, it is necessary to use pinpoint-type needle contacts to make electrical contact for testing purposes. Frequently, the distance between each corresponding probe arm and the extremity of the conductive tip differs; as a result, some of the tips will "dig" into the corresponding conductive pad on the electronic circuit, while other tips may not make sufficient electrical contact at all. It is therefore desirable to provide some means for adjusting for slight changes in the distance between the end of the conductive tip and the metallic pad to be contacted by the tip on the circuit under test, and to further provide some flexure in the tip so as to prevent destruction of the metallic contact pad.
Prior art patents of interest with respect to the integrated circuit testing field include the following: U.S. Pat. Nos. 3,930,809 to Evans; 3,891,924 to Ardezzone et al; 3,560,907 to Heller; and 3,445,770 to Harmon.